Entity Framework Validation confusion - maximum string length of '128'

Question

I'm faced with a confusing problem where in my Edit or Create action result methods, EF4 will throw a DbEntityValidationException with the inner message stating:

The field Body must be a string or array type with a maximum length of '128'.

The model in question looks like this:

[Table("tblArticles")] public class Article {     [Key]     public int ID { get; set; }     [Required(ErrorMessage="Title must be included")]     public string Title { get; set; }     [AllowHtml]     public string Body { get; set; }     [Required(ErrorMessage="Start Date must be specified")]     [Display(Name="Start Date")]     [DisplayFormat(DataFormatString="dd-mm-yyyy")]     public DateTime? StartDate { get; set; }     [Required(ErrorMessage = "End Date must be specified")]     [Display(Name = "End Date")]     public DateTime? EndDate { get; set; }     public int Priority { get; set; }     public bool Archived { get; set; }      public virtual ICollection<ArticleImage> Images { get; set; } } 

The "Body" field in the actual database is of type Text, so there's no obvious limit there. The data that I'm trying to post is this:

<p> This is an example to confirm that new articles are looking right.</p> <p> <img alt="" src="http://www.google.co.nz/logos/2011/houdini11-sr.jpg" style="width: 160px; height: 56px; float: left;" /></p> 

An example of the Edit method looks like this:

[HttpPost] public ActionResult Edit(Article article) {     if (ModelState.IsValid)     {         try         {             articleRepository.Update(article);         }         catch (DbEntityValidationException dbevEx)         {             ErrorSignal.FromCurrentContext().Raise(dbevEx);             ModelState.AddModelError("FORM", dbevEx);             return View("Edit", article);         }         // Other exception handling happens...     }      return RedirectToAction("Index"); } 

And finally, the method that actually does the grunt work is:

public void Update(T Entity) {     dbset.Attach(Entity);     db.Entry(Entity).State = System.Data.EntityState.Modified;     db.Commit(); } 

I can't see anything in code or in the database that might be causing the problem, so where else should I look?

Answer 1

Default length of string field in code first is 128. If you are using EF validation it will throw exception. You can extend the size by using:

[StringLength(Int32.MaxValue)] public string Body { get; set; } 

This post became somehow popular so I'm adding second approach which also works:

[MaxLength] public string Body { get; set; } 

StringLengthAttribute is from System.ComponentModel.DataAnnotations assembly and MaxLengthAttribute is from EntityFramework assembly (EF 4.1).